Cleaning Apparatus

ABSTRACT

The invention provides an apparatus and method for use in the cleaning of soiled substrates, the apparatus comprising a casing which contains a rotatably mounted cylindrical cage concentrically located within a rotatably mounted cylindrical drum having a greater diameter than the basket, wherein the cage and the drum are concentrically located within a stationary cylindrical drum having a greater diameter than the rotatably mounted drum, wherein the casing includes access means, allowing access to the interior of the cylindrical basket, and wherein the rotatably mounted cylindrical cage and the rotatably mounted cylindrical drum are adapted to rotate independently. The method involves cleaning the soiled substrate by treatment of the moistened substrate with a formulation comprising solid particulate cleaning material, the formulation being free of organic solvents, and the method being carried out using the apparatus of the invention, and the apparatus and method find particular application in the cleaning of textile fabrics.

FIELD OF THE INVENTION

The present invention relates to the cleaning of substrates using asolvent-free cleaning system which requires the use of only limitedquantities of water. Most particularly, the invention is concerned withthe cleaning of textile fibres by means of such a system, and providesan apparatus adapted for use in this context.

BACKGROUND TO THE INVENTION

Dry cleaning is a process of major importance within the textileindustry, specifically for the removal of hydrophobic stains which aredifficult to remove by traditional aqueous washing methods. However,most commercial dry cleaning systems currently employ toxic andpotentially environmentally harmful halocarbon solvents, such asperchloroethylene. The use of these solvents, and the need for theirstorage, treatment, and/or disposal creates major effluent problems forthe industry, and this inevitably increases costs.

More recently, the use of carbon dioxide as an alternative to suchsystems has been reported. Thus, systems which employ liquid carbondioxide in combination with surfactants containing a CO₂-philicfunctional moiety have been proposed, whilst the use of moreconventional surfactants in combination with supercritical carbondioxide has also been disclosed. However, a major problem with carbondioxide is its lower solvent power relative to other solvents.Furthermore, some of the procedures rely on the use of high pressuresystems, and this is a clear disadvantage, since it presents an inherentsafety risk, thereby lessening the attractiveness of the procedures.

Even more widely used are aqueous cleaning processes, which do notsuffer from the disadvantages associated with the use of potentiallytoxic solvents or high pressure carbon dioxide systems, but still createvery significant environmental difficulties in terms of the vastquantities of aqueous effluent which are generated. As a consequence,the use of these aqueous cleaning processes necessitates the developmentof sophisticated waste treatment systems.

In the light of the difficulties and disadvantages associated withtraditional aqueous and dry cleaning processes, the present inventorshave previously devised a new approach to the problem, which allows thedeficiencies demonstrated by the methods of the prior art to be overcomeand provides a process for the cleaning of substrates, particularly forthe cleaning of textile fibres. The method which is provided eliminatesthe requirement for the use of, on the one hand, potentially harmfulsolvents or carbon dioxide in either the liquid or supercritical stateor, on the other hand, large volumes of aqueous fluids, but is stillcapable of providing an efficient means of cleaning and stain removal,whilst also yielding economic and environmental benefits. The processemploys a cleaning formulation which is essentially free of organicsolvents and requires the use of only limited amounts of water.

Thus, in WO-A-2007/128962 there is disclosed a method and formulationfor cleaning a soiled substrate, the method comprising the treatment ofthe moistened substrate with a formulation comprising a multiplicity ofpolymeric particles, wherein the formulation is free of organicsolvents. Preferably, the substrate is wetted so as to achieve asubstrate to water ratio of between 1:0.1 to 1:5 w/w, and optionally,the formulation additionally comprises at least one cleaning material,which typically comprises a surfactant, which most preferably hasdetergent properties. In preferred embodiments, the substrate comprisesa textile fibre and the polymeric particles may, for example, compriseparticles of nylon, most preferably in the form of nylon chips.

The use of this cleaning method, however, presents a requirement for thecleaning chips to be efficiently separated from the cleaned substrate atthe conclusion of the cleaning operation, and it is this issue that isaddressed by the present invention. It has been the concern of thepresent inventors to provide an apparatus which facilitates theefficient cleaning of soiled substrates using the method ofWO-A-2007/128962, but which additionally allows for the efficientseparation of the substrate from the cleaning media at the conclusion ofthe cleaning process. This has now been achieved by means of theapparatus of the present invention, which provides a novel designrequiring the use of two internal drums capable of independent rotation,and which finds application in both industrial and domestic cleaningprocesses.

SUMMARY OF THE INVENTION

Thus, according to a first aspect of the present invention, there isprovided an apparatus for use in the cleaning of soiled substrates, saidapparatus comprising a casing which contains a rotatably mountedcylindrical cage concentrically located within a rotatably mountedcylindrical drum having a greater diameter than said basket, whereinsaid cage and said drum are concentrically located within a stationarycylindrical drum having a greater diameter than said rotatably mounteddrum, wherein said casing includes access means, allowing access to theinterior of said cylindrical basket, and wherein said rotatably mountedcylindrical cage and said rotatably mounted cylindrical drum are adaptedto rotate independently.

Said access means typically comprises a hinged door mounted in thecasing, which may be opened to allow access to the inside of thecylindrical cage, and which may be closed in order to provide asubstantially sealed system. Preferably, the door includes a window.

Said stationary cylindrical drum, rotatably mounted cylindrical cage androtatably mounted cylindrical drum may be mounted vertically within saidcasing but, most preferably, are mounted horizontally within saidcasing. Consequently, in the preferred embodiment of the invention, saidaccess means is located in the front of the apparatus, providing afront-loading facility. When the stationary cylindrical drum, rotatablymounted cylindrical cage and rotatably mounted cylindrical drum arevertically mounted within the casing, the access means is located in thetop of the apparatus, providing a top-loading facility. However, for thepurposes of the further description of the present invention, it will beassumed that said stationary cylindrical drum, rotatably mountedcylindrical cage and rotatably mounted cylindrical drum are mountedhorizontally within said casing.

Said rotatably mounted cylindrical cage and said rotatably mountedcylindrical drum are adapted to rotate independently, such that saidcage and said drum may both rotate simultaneously in the same or inopposite directions. Alternatively, one of said cage or said drum mayrotate whilst the other is at rest.

Rotation of said rotatably mounted cylindrical cage and said rotatablymounted cylindrical drum is effected by use of drive means, whichtypically comprises electrical drive means, in the form of an electricmotor, adapted to drive said cage and said drum independently orsimultaneously in the same or in opposite directions. Operation of saiddrive means is effected by control means which may be programmed by anoperative.

Said stationary cylindrical drum is a similar feature to that which isfound in conventional commercial and domestic washing machines, and isadapted to provide the same functions as in said machines. Thus, saidstationary drum is connected to the standard plumbing features of theapparatus and may additionally comprise means for circulating air withinsaid apparatus, and for adjusting the temperature and humidity therein.Said means may typically include, for example, a recirculating fan, anair heater, a water atomiser and/or a steam generator. Additionally,sensing means may also be provided for determining the temperature andhumidity levels within the apparatus, and for communicating thisinformation to the control means.

Said rotatably mounted cylindrical cage comprises a plurality ofperforations in its cylindrical side walls, thereby allowing for ingressand egress of fluids, fine particulate materials and discreteparticulate materials. Said perforations typically have a diameter offrom 5-10 mm, preferably from 6-9 mm, most preferably from 7-8 mm.

The cylindrical side walls of the rotatably mounted cylindrical drum arealso perforated to permit the ingress and egress of fluids and fineparticulate materials, but are adapted so as to prevent the ingress oregress of discrete particulate materials. Consequently, the perforationstypically have a diameter of less than 5 mm, most preferably less than2.5 mm.

Said rotatably mounted cylindrical cage is of the size which is to befound in most commercially available washing machines and tumble driers,and typically has a capacity in the region of 50-500 litres. Generallysaid cage comprises a cylinder with a diameter in the region of 40-100cm, preferably 50-90 cm, most preferably 60-80 cm, and a length ofbetween 30 and 100 cm, preferably between 40 and 90 cm, most preferablyfrom 50 to 80 cm.

Said rotatably mounted cylindrical drum is concentrically locatedoutside said rotatably mounted cylindrical basket and, consequently, hasgreater cross-sectional dimensions than said basket. Thus, typicallysaid drum comprises a cylinder with a diameter in the region of 50-120cm, preferably 60-100 cm, most preferably 70-90 cm, and a length ofbetween 30 and 100 cm, preferably between 40 and 90 cm, most preferablyfrom 50 to 80 cm.

Said stationary cylindrical drum is concentrically located outside saidrotatably mounted cylindrical drum and, consequently, has greatercross-sectional dimensions, and generally slightly greater length, thansaid rotatably mounted drum. Thus, typically said drum comprises acylinder with a diameter in the region of 55-140 cm, preferably 65-105cm, most preferably 75-95 cm, and a length of between 31 and 105 cm,preferably between 41 and 95 cm, most preferably from 51 to 85 cm.

Said apparatus is designed to operate in conjunction with soiledsubstrates and cleaning media comprising a solid particulate material,which is most preferably in the form of a multiplicity of polymericparticles. Ideally, these polymeric particles should be efficientlycirculated to promote effective cleaning and the apparatus, therefore,preferably includes circulation means. Thus, the inner surface of thecylindrical side walls of said rotatably mounted cylindrical drumpreferably comprises a multiplicity of spaced apart circulation paddles,typically in the form of oblong-shaped protrusions affixed essentiallyperpendicularly to said inner surface. Said paddles are adapted so as topromote efficient circulation of said solid particulate material.Typically said apparatus comprises from 3 to 12 of said paddles.

Preferably, said apparatus additionally comprises separation meanslocated between said rotatably mounted cylindrical cage and saidrotatably mounted cylindrical drum. In a preferred embodiment of theinvention, said separation means comprises a plurality of reservoirbaffles, which are fixedly mounted between the cylindrical walls of saidrotatably mounted cylindrical cage and said rotatably mountedcylindrical drum and are adapted so as to facilitate controlled flow ofsaid solid particulate material between said cage and said drum. Mostpreferably, said apparatus comprises two spaced apart crescent shapedreservoir baffles concentrically mounted between said cage and saiddrum, and of essentially equal length to said cage, arranged at oppositesides of said cage, so as to provide spaces at two locations throughwhich ingress and egress of materials from said cage to said drum mayoccur.

In preferred embodiments of the invention, there is also providedsuction means, in order to facilitate the efficient removal of residualsolid particulate material at the conclusion of the cleaning operation.Preferably, said suction means comprises a suction chamber. Preferably,said suction chamber is located in the base of said apparatus, belowsaid stationary cylindrical drum, said rotatably mounted cylindricalcage and said rotatably mounted cylindrical drum and is adapted tooperate at the conclusion of the cleaning operation.

Preferably, said suction chamber comprises a chamber which may beextended out of the body of the apparatus, such that it may be locatedbeneath the access means through which cleaned substrate is removed fromthe apparatus of the invention, in order that residual solid particulatematerial may be collected therein, as a consequence of the combinedeffects of gravity and applied suction. Typically, suction is applied bymeans of a vacuum pump, and is activated when said suction chamber isextended out of the body of the apparatus.

Optionally, said suction means may also comprise localised suctionmeans, typically in the form of a suction gun, which may be directed tolocalised parts of the cleaned substrate so as to remove remainingresidual solid particulate cleaning material. Preferably, said suctiongun comprises a headpiece including an aperture attached to flexibletubing, though which suction may be applied.

Preferred embodiments of the invention additionally compriserecirculation means, thereby facilitating recirculation of said solidparticulate material from said suction means to said rotatably mountedcylindrical drum, for re-use in cleaning operations. Preferably, saidrecirculation means comprises ducting connecting said suction means andsaid rotatably mounted cylindrical drum. More preferably, said ductingcomprises separating means for separating said solid particulatematerial from debris removed from the soiled substrate during thecleaning process, and purification means, adapted to remove debris fromthe air flow and permit expulsion of the filtered air stream to theatmosphere. Typically, said separating means comprises a cyclone, andsaid purification means comprises a filter.

In operation, during a typical cycle, said rotatably mounted cylindricalcage and said rotatably mounted cylindrical drum are adapted to rotateindependently in the same direction during the cleaning process. Thus,solid particulate material which falls through the perforations in thebottom of said rotatably mounted cylindrical cage and between saidreservoir baffles into said rotatably mounted cylindrical drum iscarried by means of said circulation paddles to the top side of saidrotatably mounted cylindrical cage, wherein it is caused, by means ofgravity to fall between said reservoir baffles and the perforations insaid rotatably mounted cylindrical cage, back into said cage, thereby tocontinue the cleaning operation.

At the completion of the cleaning cycle, rotation of said rotatablymounted cylindrical cage continues, whilst rotation of said rotatablymounted cylindrical cage is stopped, thus allowing said solidparticulate matter to fall through the perforations in the bottom ofsaid rotatably mounted cylindrical cage and between said reservoirbaffles into said rotatably mounted cylindrical drum, where it isallowed to collect. In practice, it is found that the amount of saidsolid particulate material which accumulates in the bottom of saidrotatably mounted cylindrical drum is too great if this is allowed toremain at rest. Consequently means for removal of the material from thislocation must be provided. Optionally, this may be in the form of anassociated reservoir, wherein the material may temporarily betransferred. Preferably, however, the material is removed by frequentchanges in the direction of rotation of the drum, or by incrementalmovement of the drum in the opposite direction to the cage, whereby thesolid particulate material is retained between successive pairs ofreservoir baffles until removal of the material from the cage has beencompleted.

Thus, according to a second aspect of the present invention, there isprovided a method for cleaning a soiled substrate, said methodcomprising the treatment of the moistened substrate with a formulationcomprising solid particulate cleaning material, said formulation beingfree of organic solvents, wherein said method is carried out in anapparatus according to the first aspect of the invention.

Preferably, said method comprises the steps of:

-   -   (a) loading at least one soiled substrate into an apparatus        according to the first aspect of the invention via the access        means, said apparatus containing a solid particulate cleaning        material located in at least one of the rotatably mounted        cylindrical cage and the rotatably mounted cylindrical drum;    -   (b) closing the access means so as to provide a substantially        sealed system;    -   (c) operating the apparatus for a first cycle, wherein said        rotatably mounted cylindrical cage and said rotatably mounted        cylindrical drum are both caused to rotate in the same        direction, wherein said first cycle comprises a wash cycle;    -   (d) operating the apparatus for a second cycle, wherein said        rotatably mounted cylindrical cage continues to rotate in the        same direction, but said rotatably mounted cylindrical drum (i)        is caused to initially cease rotation and (ii) subsequently is        subjected to incremental movements in the opposite direction to        the cage, whereby the solid particulate cleaning material is        retained between successive pairs of reservoir baffles until        removal of the material from the cage has been completed,        wherein said second cycle comprises a cycle for removal of said        solid particulate cleaning material from said at least one        substrate;    -   (e) removing the cleaned at least one substrate from the        apparatus; and    -   (f) removing any remaining solid particulate cleaning material.

Preferably, said remaining solid particulate material is removed byshaking the at least one substrate in the vicinity of suction means,preferably comprising a suction chamber, wherein said remaining solidparticulate material is collected. Most particularly, said step ofremoving any remaining solid particulate cleaning material also includesthe step of applying localised suction means to localised parts of thecleaned substrate, said localised suction means preferably comprising asuction gun.

Throughout the description and claims of this specification, the words“comprise” and “contain” and variations of the words, for example“comprising” and “comprises”, means “including but not limited to”, andis not intended to (and does not) exclude other moieties, additives,components, integers or steps.

Throughout the description and claims of this specification, thesingular encompasses the plural unless the context otherwise requires.In particular, where the indefinite article is used, the specificationis to be understood as contemplating plurality as well as singularity,unless the context requires otherwise.

Features, integers, characteristics, compounds, chemical moieties orgroups described in conjunction with a particular aspect, embodiment orexample of the invention are to be understood to be applicable to anyother aspect, embodiment or example described herein unless incompatibletherewith.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be further illustrated by reference to thefollowing drawings, wherein:

FIG. 1 shows the apparatus according to the invention prior to loading asoiled substrate comprising garments into the apparatus;

FIG. 2 illustrates the apparatus according to the invention during thewash cycle of the method of the invention;

FIG. 3 depicts the apparatus according to the invention during the cycleof the method of the invention for removal of said solid particulatecleaning material;

FIG. 4 shows the apparatus according to the invention during unloadingof the cleaned substrate;

FIG. 5 illustrates the step of removing remaining solid particulatecleaning material from the substrate using the suction chamber;

FIG. 6 depicts the use of a suction gun for removal of further remainingsolid particulate cleaning material from localised parts of the cleanedsubstrate.

FIG. 7 shows a recirculation system for collecting solid particulatecleaning material and returning it to the rotatably mounted cylindricalcage and the rotatably mounted cylindrical drum; and

FIG. 8 illustrated the action of a cyclone in separating the solidparticulate cleaning material from solid waste material generated duringthe method of the invention.

DETAILED DESCRIPTION OF THE INVENTION

The apparatus according to the invention may be used for the cleaning ofany of a wide range of substrates including, for example, plasticsmaterials, leather, paper, cardboard, metal, glass or wood. In practice,however, said apparatus is principally designed for use in the cleaningof substrates comprising textile fibre garments, and has been shown tobe particularly successful in achieving efficient cleaning of textilefibres which may, for example, comprise either natural fibres, such ascotton, or man-made and synthetic textile fibres, for example nylon 6,6,polyester, cellulose acetate, or fibre blends thereof.

Most preferably, the solid particulate cleaning material comprises amultiplicity of polymeric particles. Said polymeric particles maycomprise any of a wide range of different polymers. Specifically, theremay be mentioned polyalkenes such as polyethylene and polypropylene,polyesters and polyurethanes. Preferably, however, said polymericparticles comprise polyamide particles, most particularly particles ofnylon, most preferably in the form of nylon chips or beads. Saidpolyamides are found to be particularly effective for aqueous stain/soilremoval, whilst polyalkenes are especially useful for the removal ofoil-based stains. Optionally, copolymers of the above polymericmaterials may be employed for the purposes of the invention.

Whilst, in one embodiment, the method of the invention envisages thecleaning of a soiled substrate by the treatment of a moistened substratewith a formulation which essentially consists only of a multiplicity ofpolymeric particles, in the absence of any further additives, optionallyin other embodiments the formulation employed may additionally compriseat least one cleaning material. Preferably, the at least one cleaningmaterial comprises at least one surfactant. Preferred surfactantscomprise surfactants having detergent properties. Said surfactants maycomprise anionic, cationic and/or non-ionic surfactants. Optionally,said at least one cleaning material is mixed with said polymericparticles but, in a preferred embodiment, each of said polymericparticles is coated with said at least one cleaning material.

Various nylon homo- or co-polymers may be used, including Nylon 6 andNylon 6,6. Preferably, the nylon comprises Nylon 6,6 homopolymer havinga molecular weight in the region of from 5000 to 30000 Daltons,preferably from 10000 to 20000 Daltons, most preferably from 15000 to16000 Daltons.

The polymeric particles are of such a shape and size as to allow forgood flowability and intimate contact with the textile fibre. A varietyof shapes of particles can be used, such as cylindrical, spherical orcuboid; appropriate cross-sectional shapes can be employed including,for example, annular ring, dog-bone and circular. The particles may havesmooth or irregular surface structures and can be of solid or hollowconstruction. Particles are preferably of such a size as to have anaverage mass in the region of 5-50 mg, more preferably from 10-30 mg. Inthe case of the most preferred chips, the preferred average particlediameter is in the region of from 1.5-6.0 mm, more preferably from2.0-5.0 mm, most preferably from 2.5-4.5 mm, and the length of thecylindrical chips is preferably in the range from 2.0-6.0 mm, morepreferably from 3.0-5.0 mm, and is most preferably in the region of 4.0mm.

Prior to treatment according to the method of the invention, the soiledsubstrate is moistened by wetting with water, in order to provideadditional lubrication to the cleaning system and thereby improve thetransport properties within the system. Thus, more efficient transfer ofthe at least one cleaning material to the substrate is facilitated, andremoval of soiling and stains from the substrate occurs more readily.Most conveniently, the substrate may be wetted simply by contact withmains or tap water. Preferably, the wetting treatment is carried out soas to achieve a substrate to water ratio of between 1:0.1 to 1:5 w/w;more preferably, the ratio is between 1:0.2 and 1:2, with particularlyfavourable results having been achieved at ratios such as 1:0.2, 1:1 and1:2. However, in some circumstances, successful results can be achievedwith substrate to water ratios of up to 1:50, although such ratios arenot preferred in view of the significant amounts of effluent which aregenerated.

The method of the invention has the advantage that, other than thisaqueous treatment, it is carried out in the absence of addedsolvents—most notably in the absence of organic solvents—and,consequently, it shows distinct advantages over the methods of the priorart in terms of safety and environmental considerations, as well as ineconomic terms. However, whilst the formulation employed in the claimedmethod is free of organic solvents, in that no such solvents are addedto the formulation, it will be understood that trace amounts of suchsolvents may inevitably be present in the polymeric particles, thesubstrate, the water, or other additives, such as cleaning materials, soit is possible that the cleaning formulations and baths may not beabsolutely free of such solvents. However, such trace amounts areinsignificant in the context of the present invention, since they do nothave any impact on the efficiency of the claimed process, nor do theycreate a subsequent effluent disposal problem and the formulation is,therefore, seen to be essentially free of organic solvents.

The apparatus and the method of the present invention may be used foreither small or large scale batchwise processes and find application inboth domestic and industrial cleaning processes.

In the method according to the second aspect of the invention, the ratioof solid particulate cleaning material to substrate is based on anominal “liquor ratio” in terms of a conventional dry cleaning system,with the preferred ratio being in the range of from 30:1 to 0.1:1 w/w,preferably in the region of from 10:1 to 1:1 w/w, with particularlyfavourable results being achieved with a ratio of between 5:1 and 1:1w/w, and especially at around 4:1 w/w. Thus, for example, for thecleaning of 5 g of fabric, 20 g of polymeric particles, optionallycoated with surfactant, would be employed.

As previously noted, the method of the invention finds particularapplication in the cleaning of textile fibres. The conditions employedin such a cleaning system are very much in line with those which applyto the conventional dry cleaning of textile fibres and, as aconsequence, are generally determined by the nature of the fabric andthe degree of soiling. Thus, typical procedures and conditions for thewash cycle are in accordance with those which are well known to thoseskilled in the art, with fabrics generally being treated according tothe method of the invention at, for example, temperatures of between 30and 90° C. for a duration of between 20 minutes and 1 hour in thesubstantially sealed system provided by the apparatus according to thefirst aspect of the invention.

The cycle for removal of solid particulate material may be performed atroom temperature and it has been established that optimum results areachieved at cycle times of between 2 and 30 minutes, preferably between5 and 15 minutes.

In the embodiment of the invention wherein the formulation comprises atleast one cleaning material, it is preferred that the polymericparticles should be coated with the at least one surfactant, in order toachieve a more level distribution of the said surfactant on theparticles and, consequently, on the substrate, as the particles contactthe substrate during the cleaning process. Typically, this coatingprocess requires that the polymeric particles should be mixed with0.5%-10%, preferably 1%-5%, most preferably around 2% of the at leastone surfactant, and the resulting mixture held at a temperature ofbetween 30° and 70° C., preferably 40° and 60° C., most preferably inthe region of 50° C., for a time of between 15 and 60 minutes,preferably between 20 and 40 minutes, with the most satisfactory resultsbeing obtained when the treatment is carried out for approximately 30minutes.

The results obtained are very much in line with those observed whencarrying out conventional aqueous and dry cleaning procedures withtextile fabrics. The extent of cleaning and stain removal achieved withfabrics treated by the method of the invention is seen to be very good,with particularly outstanding results being achieved in respect ofhydrophobic stains and aqueous stains and soiling, which are oftendifficult to remove. The method also finds application in wash-offprocedures applied to textile fibres subsequent to dyeing processes, andin scouring processes which are used in textile processing for theremoval of dirt, sweat, machine oils and other contaminants which may bepresent following processes such as spinning and weaving. The attendantdrawbacks associated with the use of solvents in conventional drycleaning processes, in terms of both cost and environmentalconsiderations, are avoided, whilst the volumes of water required aresignificantly lower than those associated with the use of conventionalaqueous washing procedures, again offering significant advantages interms of cost and environmental benefits.

The method of the invention has been shown to be particularly successfulin the removal of cleaning material from the cleaned substrate afterprocessing and tests with cylindrical nylon chips comprising nylon 6,6polymer have indicated bead removal efficacy of 99.95% from a 5 minutecycle.

Additionally, it has been demonstrated that re-utilisation of thepolymer particles is possible, and that particles can be satisfactorilyre-used in the cleaning procedure, although some deterioration inperformance is generally observed following three uses of the particles.When re-using particles, optimum results are achieved when usingparticles coated with the at least one coating material which are thenre-coated prior to re-use.

Referring to the figures provided herewith, there is seen in FIG. 1 anapparatus 1 according to the invention comprising a casing 2 and door 3including window 4, and housed within the casing is a rotatably mountedcylindrical cage 5 having perforations 6. With the door 3 in the openposition, garment 7 may be placed in rotatably mounted cylindrical cage5.

FIG. 2 provides an illustration of apparatus 1 during the wash cyclewherein garments 7 are in the rotatably mounted cylindrical cage 5 whichis rotating in the direction of arrows A, with the rotatably mountedcylindrical drum 8 rotating in the same direction, as indicated byarrows B. Nylon chips 9 are also in the rotatably mounted cylindricalcage 5 and fall through the perforations 6 in the bottom of said cage 5through the lower gap between reservoir baffles 10 into the rotatablymounted cylindrical drum 8, and are then carried by means of circulationpaddles 11 by rotation of the drum 8 to the top side of the rotatablymounted cylindrical cage 5, thereby re-entering said cage via the uppergap between reservoir baffles 10 to again take part in the wash cycle.The stationary cylindrical drum (not shown) is of greater diameter thansaid rotatably mounted cylindrical cage 5 and said rotatably mountedcylindrical drum 8, and located concentrically around said rotatablymounted cylindrical drum.

In FIG. 3, there is shown the chip removal cycle, wherein chips 9 in therotatably mounted cylindrical cage 5, rotating in the direction ofarrows A, fall through the perforations 6 in the bottom of the cage 5through the lower gap between reservoir baffles 10 into the rotatablymounted cylindrical drum 8. Drum 8 moves incrementally in the directionof arrow C, opposite to the direction of rotation of cage 5, therebyallowing chips 9 to be retained between circulation paddles 11 in thespace between drum 8 and reservoir baffles 10.

At the conclusion of the wash and chip removal cycles, as shown in FIG.4, the door 3 may be opened to allow removal of garments 7. At the sametime, suction chamber 12, incorporating garment mesh 13, which retainsthe garments 7 but allows chips to fall to the bottom of the chamber, isalso opened, to facilitate removal of remaining chips attached togarments 7.

As seen from FIG. 5, the garments 7 may be shaken to cause the remainingchips 9 to become detached and collected, by means of the appliedsuction, in the suction chamber 12.

FIG. 6 illustrates the use of a suction gun comprising a headpiece 14and flexible tubing 15 in the removal of remaining cleaning chips fromshirt pocket 16.

Turning to FIG. 7, there is illustrated a recirculation systemcomprising ducting 17, 18, 19 cyclone 20, filter 21 and exhaust pipe 22.Thus, in operation, nylon chips are collected in suction chamber 12 andtransferred via ducting 17 to cyclone 20, wherein lint and other lightersolid particulate material is separated and exits the system via ducting18, filter 21 and exhaust pipe 22, whilst the heavier nylon chips fallthrough ducting 19, and are thereby returned to the rotatably mountedcylindrical drum 8.

Finally, in FIG. 8 can be seen the action of cyclone 20, wherein themixture of nylon chips and other lighter solid particulate materialenters to cyclone through ducting 17 and is separated by the action ofthe cyclone, such that the lighter material 23 exits via ducting 18,whilst the nylon chips 9 fall through ducting 19.

The method of the invention will now be exemplified, though without inany way limiting the scope of the invention, by reference to thefollowing examples:

EXAMPLES

Experiments were conducted in order to ascertain cleaning efficiencyusing the apparatus and method according to the invention.

Example 1

The polymer particles comprised cylindrical nylon chips comprising Nylon6,6 polymer having a molecular weight in the region of 15000-16000Daltons, with average dimensions of 4 mm in length and 2-3 mm indiameter, and an average particle weight of 30-40 mg.

The fabric to be cleaned comprised soiled and stained Nylon 6,6 fibres,and the wetted dyed fabric was loaded into an apparatus according to theinvention containing 75 g (air dry mass) of polymer particles. Thetemperature was raised to 40° C. and maintained at 40° C. for 10minutes, then increased to 70° C. at a rate of 2° C. per minute, andthen maintained at 70° C. for 20 minutes to complete the wash cycle,after which time the cycle for removal of the nylon chips was operatedfor 5 minutes before the fabric was removed from the apparatus, rinsedand dried. Complete removal of the soiling and staining was achieved andthe fabric was found to be free of residual nylon chips.

Example 2

The fabric to be cleaned comprised a soiled cloth of mercerised cottonstained with coffee in an aqueous transport medium. This pre-soiledfabric sample was placed in an apparatus according to the inventioncontaining 75 g (air dry mass) of polymer particles comprisingcylindrical chips of Nylon 6,6 polymer, with average dimensions of 4 mmin length and 4 mm in diameter. The pre-soiled fabric sample was wettedwith tap water before commencement of cleaning to give a substrate towater ratio of 1:1. The apparatus was operated on the cleaning cycle for30 minutes to a maximum of 70° C. with a cooling stage at the end of thecycle, then the cycle for removal of the nylon chips was operated for 5minutes. Once this was complete, the cleaned fabric was removed from theapparatus and dried flat. The degree of staining of the cloth was verysignificantly reduced following the cleaning process.

Example 3

The fabric to be cleaned comprised a soiled cloth of mercerised cottonstained with city street dirt in an aqueous transport medium. This presoiled fabric sample was placed in an apparatus according to theinvention with 75 g (air dry mass) of polymer particles comprisingcylindrical chips of Nylon 6,6 polymer, with average dimensions of 4 mmin length and 4 mm in diameter. The pre-soiled fabric sample was wettedwith tap water before commencement of cleaning to give a substrate towater ratio of 1:2. The apparatus was operated on the cleaning cycle for30 minutes to a maximum of 70° C. with a cooling stage at the end of thecycle, then the cycle for removal of the nylon chips was operated for 5minutes. Once this was complete, the cleaned fabric was removed from theapparatus and dried flat. A significant reduction in numbers of dirtparticles was observed after the cleaning process had taken place.

Example 4

The fabrics to be cleaned comprised soiled cloths (cotton and polyesterstained with coffee, soil, boot polish, ball point pen, lipstick, tomatoketchup and grass). Each pre-soiled fabric sample was placed in anapparatus according to the invention with 75 g (air dry mass) of thepolymer particles (cylindrical nylon chips comprising nylon 6,6 polymer,with average dimensions of 4 mm in length and 4 mm in diameter). Eachpre-soiled fabric sample was wetted with mains or tap water beforecleaning commenced to give a substrate to water ratio of 1:1. Theapparatus was operated on the cleaning cycle for 30 minutes at a maximumtemperature of 70° C. with a cooling stage at the end of the cycle, thenthe cycle for removal of the nylon chips was operated for 5 minutes.Once this was complete, the cleaned fabric was removed from theapparatus and dried flat. In each case, the degree of staining of thefabric was significantly reduced.

Example 5

The fabric to be cleaned comprised a soiled cloth (cotton stained withcity street dirt in an aqueous transport medium). This pre soiled fabricsample was placed in an apparatus according to the invention with 75 g(air dry mass) of the polymer particles (cylindrical nylon chipscomprising nylon 6,6 polymer, with average dimensions of 4 mm in lengthand 4 mm in diameter). The pre-soiled fabric sample was wetted withmains or tap water before cleaning commenced to give a substrate towater ratio of 1:2. The apparatus was operated on the cleaning cycle for30 minutes to a maximum temperature of 70° C. with a cooling stage atthe end of the cycle, then the cycle for removal of the nylon chips wasoperated for 5 minutes. Once this was complete, the cleaned fabric wasremoved from the apparatus and dried flat. The amount of removal wasvery significant was measured by the change in colour strength valuesbetween the fabric before and after cleaning.

Example 6

The fabric to be cleaned comprised a large soiled cloth (cotton stainedwith boot polish, soil, coffee and tomato ketchup). This pre-soiledfabric sample was placed in an apparatus according to the invention with500 g (air dry mass) of the polymer particles (cylindrical nylon chipscomprising nylon 6,6 polymer, with average dimensions of 4 mm in lengthand 4 mm in diameter). The pre-soiled fabric sample was wetted withmains or tap water before cleaning commenced to give a substrate towater ratio of 1:0.2. The apparatus was operated on the cleaning cyclefor 30 minutes to a maximum temperature of 70° C. with a cooling stageat the end of the cycle, then the cycle for removal of the nylon chipswas operated for 5 minutes. Once this was complete, the cleaned fabricwas removed from the apparatus and dried. The degree of staining of thefabric was significantly reduced.

Example 7

The fabric to be scoured comprised a greige cotton cloth. This greigefabric sample was placed in an apparatus according to the invention with75 g (air dry mass) of the polymer particles (cylindrical nylon chipscomprising nylon 6,6 polymer, with average dimensions of 4 mm in lengthand 4 mm in diameter). The greige fabric sample was wetted with mains ortap water before cleaning commenced to give a substrate to water ratioof 1:2. The apparatus was operated on the cleaning cycle for 30 minutesto a maximum temperature of 70° C. with a cooling stage at the end ofthe cycle, then the cycle for removal of the nylon chips was operatedfor 5 minutes. Once this was complete, the cleaned fabric was removedfrom the apparatus and dried flat. The difference in colour betweenconventionally scoured fabric and the fabric cleaned using the novelprocess was shown by the change in colour strength values between thefabrics to be very significant.

Example 8

Further experiments were carried out in order to determine theefficiency of removal of cleaning material from the substrates aftertreatment with the cleaning material. The tests were carried out usingpolyester/cotton shirts, since these provided more testing substratesthan cloths, due to the potential for retention of cleaning materials increvices and pockets.

Experiment A

A polyester/cotton shirt wetted with mains or tap water to give asubstrate to water ratio of 1:2 was loaded into an apparatus accordingto the invention containing 75 g (air dry mass) of polymer particles(cylindrical nylon chips comprising nylon 6,6 polymer, with averagedimensions of 4 mm in length and 4 mm in diameter). The apparatus wasoperated on the cleaning cycle for 2 minutes to ensure that the shirtwas thoroughly covered with chips. During this cycle both the innerrotatably mounted cylindrical cage and outer rotatably mountedcylindrical drum were rotated together, causing thorough mixing of theshirt and chips. The shirt with chips still attached was carefullyremoved from the machine and weighed as a whole. The mass of the shirtwas then deducted from the recorded weight to give the mass of chips,which was then converted to a numerical figure showing the approximatenumber of chips.

Experiment B

A polyester/cotton shirt wetted with mains or tap water to give asubstrate to water ratio of 1:2 was loaded into an apparatus accordingto the invention containing 75 g (air dry mass) of polymer particles(cylindrical nylon chips comprising nylon 6,6 polymer, with averagedimensions of 4 mm in length and 4 mm in diameter). The apparatus wasoperated on the cleaning cycle for 2 minutes to ensure that the shirtwas thoroughly covered with chips. During this cycle both the innerrotatably mounted cylindrical cage and outer rotatably mountedcylindrical drum were rotated together, causing thorough mixing of theshirt and chips. The cycle for removal of the nylon chips was thenoperated for cycles of 3 and 5 minutes. In the course of these cycles,the outer rotatably mounted cylindrical drum was kept stationary, whilethe inner rotatably mounted cylindrical cage containing the shirt wasrotated with frequent changes of direction. The shirt was carefullyremoved from the machine without shaking and the chips were removed andcounted. In addition, the number of chips in the pocket of the shirt wasalso counted.

The results of these tests are set out in Tables 4, 5 and 6.

TABLE 4 Number of Chips attached to Shirt after Two Minute Wash CycleTrial Number of Beads 1 29000 2 23000 3 27000 4 37000 5 33000 Average29800

TABLE 5 Number of Chips attached to Shirt after Two Minute Wash Cycleand Three Minute Chip Removal Cycle Number of Beads Trial Number ofBeads in Pocket 1 247 1 2 269 0 3 112 0 4 167 0 5 133 0 Average 186 0

TABLE 6 Number of Chips attached to Shirt after Two Minute Wash Cycleand Five Minute Chip Removal Cycle Trial Number of Beads 1 6 2 11 3 3 438 5 17 Average 15

From the above data, the percentage removal of chips from the shirtbetween the end of the wash cycle and the end of the chip removal cyclemay be calculated. The values used for the calculation are the averagenumber of beads after two minutes washing and the average number ofbeads remaining after the chip removal cycle, and the value iscalculated from the following formula:

${{Percentage}\mspace{14mu} {removal}} = {\frac{\begin{matrix}{{{Number}\mspace{14mu} {of}\mspace{14mu} {beads}\mspace{14mu} {after}\mspace{14mu} {wash}} -} \\{{Number}\mspace{14mu} {of}\mspace{14mu} {beads}\mspace{14mu} {after}\mspace{14mu} {separation}}\end{matrix}}{{Number}\mspace{14mu} {of}\mspace{14mu} {beads}\mspace{14mu} {after}\mspace{14mu} {separation}} \times 100}$

Using this formula, it was calculated that the percentage removal bymeans of the three minute chip removal cycle was 99.38% while thepercentage removal via the five minute chip removal cycle was 99.95%.

From further observations, it appears that the majority of the chipremoval occurs within the first few seconds of the cycle and, whilstextended tumbling improves the efficacy, there seems to be little valuein extending the cycle beyond five minutes. The present process achievesa satisfactory level of performance, with good removal even from theshirt pocket.

1. An apparatus for use in the cleaning of soiled substrates, saidapparatus comprising a casing which contains a rotatably mountedcylindrical cage concentrically located within a rotatably mountedcylindrical drum having a greater diameter than said basket, whereinsaid cage and said drum are concentrically located within a stationarycylindrical drum having a greater diameter than said rotatably mounteddrum, wherein said casing includes access means, allowing access to theinterior of said cylindrical basket, and wherein said rotatably mountedcylindrical cage and said rotatably mounted cylindrical drum are adaptedto rotate independently.
 2. An apparatus as claimed in claim 1 whereinsaid access means may be closed so as to provide a substantially sealedsystem.
 3. (canceled)
 4. An apparatus as claimed in claim 1 wherein saidstationary cylindrical drum, said rotatably mounted cylindrical cage androtatably mounted cylindrical drum are mounted horizontally within saidcasing.
 5. An apparatus as claimed in claim 1 wherein said rotatablymounted cylindrical cage comprises a plurality of perforations in itscylindrical side walls, thereby allowing for ingress and egress offluids, fine particulate materials and discrete particulate materials.6-8. (canceled)
 9. An apparatus as claimed in claim 1 wherein saidrotatably mounted cylindrical drum comprises a plurality of perforationsin its cylindrical side walls, thereby allowing for ingress and egressof fluids and fine particulate materials but preventing the ingress oregress of discrete particulate materials. 10-11. (canceled)
 12. Anapparatus as claimed in claim 1 wherein said rotatably mountedcylindrical cage has a capacity in the region of 50-500 litres. 13-16.(canceled)
 17. An apparatus as claimed in claim 1 wherein rotation ofsaid rotatably mounted cylindrical cage and said rotatably mountedcylindrical drum is effected by use of drive means, wherein operation ofsaid drive means is optionally effected by control means. 18-20.(canceled)
 21. An apparatus as claimed in claim 1 which comprisescirculation means.
 22. An apparatus as claimed in claim 21 wherein theinner surface of the cylindrical side walls of said rotatably mountedcylindrical drum comprises a multiplicity of spaced apart circulationpaddles to serve as circulation means.
 23. (canceled)
 24. An apparatusas claimed in claim 1 wherein said apparatus additionally comprisesseparation means, wherein said separation means optionally comprises aplurality of reservoir baffles which are fixedly mounted between thecylindrical walls of said rotatably mounted cylindrical cage and saidrotatably mounted cylindrical drum. 25-26. (canceled)
 27. An apparatusas claimed in claim 1 which comprises suction means. 28-32. (canceled)33. An apparatus as claimed in claim 1 which additionally comprisesrecirculation means, wherein said recirculation means optionallycomprises ducting connecting said suction means and said rotatablymounted cylindrical drum, said ducting comprises separating means andpurification means and said separating means comprises a cyclone andsaid purification means comprises a filter. 34-36. (canceled)
 37. Amethod for cleaning a soiled substrate, said method comprising thetreatment of the moistened substrate with a formulation comprising solidparticulate cleaning material, said formulation being free of organicsolvents, wherein said method is carried out in an apparatus accordingto claim
 1. 38. A method for cleaning a soiled substrate, said methodcomprising the steps of: (a) loading at least one soiled substrate intoan apparatus as claimed in claim 1 via the access means, said apparatuscontaining a solid particulate cleaning material located in at least oneof the rotatably mounted cylindrical cage and the rotatably mountedcylindrical drum; (b) closing the access means so as to provide asubstantially sealed system; (c) operating the apparatus for a firstcycle, wherein said rotatably mounted cylindrical cage and saidrotatably mounted cylindrical drum are both caused to rotate in the samedirection, wherein said first cycle comprises a wash cycle; (d)operating the apparatus for a second cycle, wherein said rotatablymounted cylindrical cage continues to rotate in the same direction, butsaid rotatably mounted cylindrical drum (i) is caused to initially ceaserotation and (ii) subsequently is subjected to incremental movements inthe opposite direction to the cage, whereby the solid particulatecleaning material is retained between successive pairs of reservoirbaffles until removal of the material from the cage has been completed,wherein said second cycle comprises a cycle for removal of said solidparticulate cleaning material from said at least one substrate; (e)removing the cleaned at least one substrate from the apparatus; and (f)removing any remaining solid particulate cleaning material. 39-41.(canceled)
 42. A method as claimed in any claim 37 wherein said at leastone soiled substrate comprises at least one textile fibre garment andsaid solid particulate cleaning material comprises a multiplicity ofpolymeric particles, and wherein said solid particulate cleaningmaterial comprises at least one cleaning material, and said soiledsubstrate is moistened by wetting with water prior to commencingcleaning operations. 43-57. (canceled)